Long-term outcomes of IMiD-based trials in patients with immunoglobulin light-chain amyloidosis: a pooled analysis

Status and Future Directions of Therapeutics and Prognosis of Cardiac Amyloidosis

Accumulation of aberrant proteins in the heart causes cardiac amyloidosis, an uncommon and complicated illness. It can be classified into two main types: light chain (AL) and transthyretin (ATTR). The diagnosis of cardiac amyloidosis is challenging due to its non-specific clinical presentation and lack of definitive diagnostic tests. Diagnostic accuracy has increased with the advent of modern imaging methods, including cardiac magnetic resonance imaging (MRI) and positron emission tomography (PET) scans. Depending on the severity of cardiac amyloidosis, a number of treatments may be attempted and specified according to the subtype of amyloidosis and the presence of complications. However, there are still significant challenges in treating this condition due to its complexity and lack of effective treatments. The prognosis for patients with cardiac amyloidosis is poor. Despite recent advances in diagnosis and treatment, there is still a need for more effective treatments to improve outcomes for patients with this condition. Therefore, we aim to review the current and future therapeutics reported in the literature and among ongoing clinical trials recruiting patients with CA.

Predictors of hematologic response and survival with stem cell transplantation in AL amyloidosis: a 25-year longitudinal study

High-dose melphalan and stem cell transplantation (HDM/SCT) is an effective treatment for selected patients with AL amyloidosis. We report the long-term outcomes of 648 patients with AL amyloidosis treated with HDM/SCT over 25 years. Hematologic CR was achieved by 39% of patients. The median duration of hematologic CR was 12.3 years, and 45% of patients with a hematologic CR had no evidence of a recurrent plasma cell dyscrasia at 15 years after HDM/SCT. With a median follow-up interval of 8 years, the median event-free survival (EFS) and overall survival (OS) were 3.3 and 7.6 years, respectively. Patients with a hematologic CR had a median OS of 15 years, and 30% of these patients survived >20 years. On multivariable analysis, dFLC >180 mg/L and BM plasma cells >10% were independently associated with shorter EFS, whereas BNP >81 pg/mL, troponin I >0.1 ng/mL, and serum creatinine >2.0 mg/dL were independently associated with shorter OS. We developed a prognostic score for EFS, which incorporated dFLC >180 mg/L and BMPC% >10% as adverse risk factors. Patients with low-risk (0 factors), intermediate-risk (1 factor), and high-risk (2 factors) disease had median EFS estimates of 5.3, 2.8, and 1.0 years, respectively (p<0.001). The 100-day treatment-related mortality rate was 3% in the latest treatment period (2012-2021), and the 25-year risk of t-MDS/AML was 3%. We conclude that HDM/SCT induces durable hematologic responses and prolonged survival with improved safety in selected patients with AL amyloidosis. This article is protected by copyright. All rights reserved.

Molecular Mechanism of Pathogenesis and Treatment Strategies for AL Amyloidosis

In amyloid light-chain (AL) amyloidosis, small B-cell clones (mostly plasma cell clones) present in the bone marrow proliferate and secrete unstable monoclonal free light chains (FLCs), which form amyloid fibrils that deposit in the interstitial tissue, resulting in organ injury and dysfunction. AL amyloidosis progresses much faster than other types of amyloidosis, with a slight delay in diagnosis leading to a marked exacerbation of cardiomyopathy. In some cases, the resulting heart failure is so severe that chemotherapy cannot be administered, and death sometimes occurs within a few months. To date, many clinical studies have focused on therapeutics, especially chemotherapy, to treat this disease. Because it is necessary to promptly lower FLC, the causative protein of amyloid, to achieve a hematological response, various anticancer agents targeting neoplastic plasma cells are used for the treatment of this disease. In addition, many basic studies using human specimens to elucidate the pathophysiology of AL have been conducted. Gene mutations associated with AL, the characteristics of amyloidogenic LC, and the structural specificity of amyloid fibrils have been clarified. Regarding the mechanism of cellular and tissue damage, the mass effect due to amyloid deposition, as well as the toxicity of pre-fibrillar LC, is gradually being elucidated. This review outlines the pathogenesis and treatment strategies for AL amyloidosis with respect to its molecular mechanisms.

Immunoglobulin light chain amyloidosis: 2022 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include heart failure with preserved ejection fraction, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical smoldering multiple myeloma or monoclonal gammopathy of undetermined significance (MGUS)."

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for the diagnosis of AL amyloidosis. Invasive organ biopsy is not required in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP or BNP), serum troponin T (or I), and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four groups of similar size; median survivals are 73, 35, 15, and 5 months.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Current first-line therapy with the best outcome is daratumumab, bortezomib, cyclophosphamide, and dexamethasone. The goal of therapy is a complete response (CR). In patients failing to achieve this depth of response options for consolidation include pomalidomide, stem cell transplantation, venetoclax, and bendamustine.

FUTURE CHALLENGES

Delayed diagnosis remains a major obstacle to initiating effective therapy prior to the development of end-stage organ failure. Trials of antibodies to catabolize deposited fibrils are underway.

Cardiac Amyloidosis Treatment

Cardiac amyloidosis (CA) is a restrictive cardiomyopathy with a traditionally poor prognosis. Until recently, CA treatment options were limited and consisted predominantly of managing symptoms and disease-related complications. However, the last decade has seen significant advances in disease-modifying therapies, increased awareness of CA, and improved diagnostic methods resulting in earlier diagnoses. In this review, we provide an overview of current and experimental treatments for the predominant types of CA: transthyretin cardiac amyloidosis (ATTR-CA) and immunoglobulin light chain (AL)-mediated CA (AL-CA).

The mainstay of AL-CA treatment is proteasome inhibitor-based chemotherapy with daratumumab and, when feasible, autologous stem cell transplantation. For ATTR-CA, the stabilizer tafamidis is the only US Food and Drug Administration (FDA)-approved treatment. However, promising novel therapies on the horizon target various points in the ATTR-CA amyloidogenic cascade. These include transthyretin gene (TTR) silencing agents to prevent TTR formation, TTR tetramer stabilization and inhibition of oligomer aggregation to prevent fibril formation, anti-TTR fiber antibodies, and amyloid degradation. For end-stage CA, advanced interventions may need to be considered, including heart, heart-kidney, and, for hereditary ATTR-CA, heart-liver transplantation. Despite the evolution of treatment options, CA management remains complex due to patient frailty and therapeutic side effects or intolerance with advanced cardiac disease. This is particularly relevant for those with AL-CA, when active teamwork between the hematologist-oncologist and the cardiologist is critical for treatment success. Often, referral to an expert center is necessary for timely diagnosis, initiation of treatment, and participation in clinical trials.

Suitability for Kidney Transplantation in AL Amyloidosis: A Survey Study of Transplant and Amyloidosis Physicians

Background

Historically, kidney transplantation has been considered inappropriate for most patients with AL amyloidosis-associated kidney failure because of concerns about recurrent disease in the allograft and poor long-term survival. With improvements in rates and durability of hematologic responses and survival that have accompanied treatment advances, a greater proportion of patients with AL amyloidosis may be suitable for kidney transplantation. However, there are no widely accepted criteria for kidney transplant eligibility for this patient population.

Methods

We administered surveys electronically to transplant nephrologists and amyloidosis experts at a geographically diverse set of academic medical centers in the United States. Questions were designed to elucidate views about suitability and timing of kidney transplantation for patients with AL amyloidosis-associated kidney failure.

Results

The survey was completed by 20 (65%) of invited amyloidosis experts and 20 (29%) of invited transplant physicians. Respondents indicated that, for patients with AL amyloidosis, most transplant nephrologists have limited experience with both determining eligibility for and providing care after kidney transplantation. Most transplant nephrologists and amyloidosis experts viewed anticipated patient survival as the most important determinant of suitability for kidney transplantation. Compared with transplant program respondents, amyloidosis program respondents reported a higher degree of confidence in determining suitability for kidney transplantation, were comfortable proceeding with kidney transplantation earlier after patients attained a hematologic response, and were less concerned about extrarenal amyloid involvement as a barrier to kidney transplantation. In both groups, most respondents indicated that there is a lack of consensus between amyloidosis and kidney transplant physicians about criteria for determining suitability for kidney transplantation.

Conclusion

Views about criteria for kidney transplantation for patients with AL amyloidosis-associated kidney failure differed between amyloidosis and transplant nephrology program respondents, with amyloidosis specialists generally favoring a less-restrictive approach to transplant eligibility. The findings suggest a need for consensus building across specialties.

Lenalidomide and dexamethasone in relapsed/refractory immunoglobulin light chain (AL) amyloidosis: results from a large cohort of patients with long follow-up

Lenalidomide and dexamethasone (RD) is a standard treatment in relapsed/refractory immunoglobulin light chain (AL) amyloidosis (RRAL). We retrospectively investigated toxicity, efficacy and prognostic markers in 260 patients with RRAL. Patients received a median of two prior treatment lines (68% had been bortezomib-refractory; 33% had received high-dose melphalan). The median treatment duration was four cycles. The 3-month haematological response rate was 31% [very good haematological response (VGHR) in 18%]. The median follow-up was 56·5 months and the median overall survival (OS) and haematological event-free survival (haemEFS) were 32 and 9 months. The 2-year dialysis rate was 15%. VGHR resulted in better OS (62 vs. 26 months, P < 0·001). Cardiac progression predicted worse survival (22 vs. 40 months, P = 0·027), although N-terminal prohormone of brain natriuretic peptide (NT-proBNP) increase was frequently observed. Multivariable analysis identified these prognostic factors: NT-proBNP for OS [hazard ratio (HR) 1·71; P < 0·001]; gain 1q21 for haemEFS (HR 1·68, P = 0·014), with a trend for OS (HR 1·47, P = 0·084); difference between involved and uninvolved free light chains (dFLC) and light chain isotype for OS (HR 2·22, P < 0·001; HR 1·62, P = 0·016) and haemEFS (HR 1·88, P < 0·001; HR 1·59, P = 0·008). Estimated glomerular filtration rate (HR 0·71, P = 0·004) and 24-h proteinuria (HR 1·10, P = 0·004) were prognostic for renal survival. In conclusion, clonal and organ biomarkers at baseline identify patients with favourable outcome, while VGHR and cardiac progression define prognosis during RD treatment.

Acquired and inherited amyloidosis: Knowledge driving patients' care

Until recently, systemic amyloidoses were regarded as ineluctably disabling and life-threatening diseases. However, this field has witnessed major advances in the last decade, with significant improvements in therapeutic options and in the availability of accurate and non-invasive diagnostic tools. Outstanding progress includes unprecedented hematological response rates provided by risk-adapted regimens in light chain (AL) amyloidosis and the approval of innovative pharmacological agents for both hereditary and wild-type transthyretin amyloidosis (ATTR). Moreover, the incidence of secondary (AA) amyloidosis has continuously reduced, reflecting advances in therapeutics and overall management of several chronic inflammatory diseases. The identification and validation of novel therapeutic targets has grounded on a better knowledge of key molecular events underlying protein misfolding and aggregation and on the increasing availability of diagnostic, prognostic and predictive markers of organ damage and response to treatment. In this review, we focus on these recent advancements and discuss how they are translating into improved outcomes. Neurological involvement dominates the clinical picture in transthyretin and gelsolin inherited amyloidosis and has a significant impact on disease course and management in all patients. Neurologists, therefore, play a major role in improving patients' journey to diagnosis and in providing early access to treatment in order to prevent significant disability and extend survival.

Management of AL amyloidosis in 2020

In amyloid light chain (AL) amyloidosis, a small B-cell clone, most commonly a plasma cell clone, produces monoclonal light chains that exert organ toxicity and deposit in tissue in the form of amyloid fibrils. Organ involvement determines the clinical manifestations, but symptoms are usually recognized late. Patients with disease diagnosed at advanced stages, particularly when heart involvement is present, are at high risk of death within a few months. However, symptoms are always preceded by a detectable monoclonal gammopathy and by elevated biomarkers of organ involvement, and hematologists can screen subjects who have known monoclonal gammopathy for amyloid organ dysfunction and damage, allowing for a presymptomatic diagnosis. Discriminating patients with other forms of amyloidosis is difficult but necessary, and tissue typing with adequate technology available at referral centers, is mandatory to confirm AL amyloidosis. Treatment targets the underlying clone and should be risk adapted to rapidly administer the most effective therapy patients can safely tolerate. In approximately one-fifth of patients, autologous stem cell transplantation can be considered up front or after bortezomib-based conditioning. Bortezomib can improve the depth of response after transplantation and is the backbone of treatment of patients who are not eligible for transplantation. The daratumumab+bortezomib combination is emerging as a novel standard of care in AL amyloidosis. Treatment should be aimed at achieving early and profound hematologic response and organ response in the long term. Close monitoring of hematologic response is vital to shifting nonresponders to rescue treatments. Patients with relapsed/refractory disease are generally treated with immune-modulatory drugs, but daratumumab is also an effective option.

Management of AL amyloidosis in 2020

In amyloid light chain (AL) amyloidosis, a small B-cell clone, most commonly a plasma cell clone, produces monoclonal light chains that exert organ toxicity and deposit in tissue in the form of amyloid fibrils. Organ involvement determines the clinical manifestations, but symptoms are usually recognized late. Patients with disease diagnosed at advanced stages, particularly when heart involvement is present, are at high risk of death within a few months. However, symptoms are always preceded by a detectable monoclonal gammopathy and by elevated biomarkers of organ involvement, and hematologists can screen subjects who have known monoclonal gammopathy for amyloid organ dysfunction and damage, allowing for a presymptomatic diagnosis. Discriminating patients with other forms of amyloidosis is difficult but necessary, and tissue typing with adequate technology available at referral centers, is mandatory to confirm AL amyloidosis. Treatment targets the underlying clone and should be risk adapted to rapidly administer the most effective therapy patients can safely tolerate. In approximately one-fifth of patients, autologous stem cell transplantation can be considered up front or after bortezomib-based conditioning. Bortezomib can improve the depth of response after transplantation and is the backbone of treatment of patients who are not eligible for transplantation. The daratumumab+bortezomib combination is emerging as a novel standard of care in AL amyloidosis. Treatment should be aimed at achieving early and profound hematologic response and organ response in the long term. Close monitoring of hematologic response is vital to shifting nonresponders to rescue treatments. Patients with relapsed/refractory disease are generally treated with immune-modulatory drugs, but daratumumab is also an effective option.

Daratumumab for relapsed AL amyloidosis-When cumulative real-world data precedes clinical trials: A multisite study and systematic literature review

OBJECTIVES

Patients with relapsed/refractory AL amyloidosis (RRAL) have poor prognosis, but emerging data shows promising results with the use daratumumab. We evaluated daratumumab treatment in RRAL in real-world setting.

METHODS

A retrospective multisite study of RRAL patients treated with daratumumab alone and in combinations.

RESULTS

Forty-nine patients, diagnosed between 1.1.2008 and 1.2.2018 were included; 27% also had multiple myeloma (MM). Revised Mayo score was ≥ 3 in 67%. Hematologic overall response rate was 81%, 64% achieved very good partial response (VGPR) or better. Concurrent active MM was associated with lower rates of VGPR (OR 0.19, 95% CI 0.04-0.81; P = .03) in a multi-variate analysis. Cardiac and renal responses were 74% and 73%, respectively. Median progression-free survival (PFS) was 28.4 months and median overall survival (OS) was not reached; 2-year PFS and OS were 68.6 ± 7.5% and 90.4 ± 4.6%, respectively. Hematologic response correlated with prolonged PFS and OS. Daratumumab was safe and well tolerated, no patients discontinued therapy due to toxicity. Our data was aligned with outcomes from a systematic literature review, which identified 10 case series (n = 517) and 2 clinical trials (n = 62) meeting prespecified criteria.

CONCLUSIONS

Our data support favorable safety tolerability and efficacy of daratumumab among non-selective RRAL patients in a real-world setting.

High rate of profound clonal and renal responses with daratumumab treatment in heavily pre-treated patients with light chain (AL) amyloidosis and high bone marrow plasma cell infiltrate

Daratumumab demonstrated activity in the treatment of AL amyloidosis in two recently concluded phase II clinical trials in relapsed and refractory patients. Its role in upfront therapy is under evaluation in a phase III study. In this report we evaluated the safety and efficacy of 28-day cycles of daratumumab (single agent or combined with bortezomib or lenalidomide) in 72 previously treated patients with multiple myeloma and AL amyloidosis. Fifty (69%) were refractory to the last line of therapy. After eight infusions of daratumumab, 59 patients (82%) achieved a hematologic response, with 12 (16%) complete responses (CRs) and 30 (42%) very good partial responses (VGPRs). After 16 infusions, the quality of response improved with 22 patients (30%) achieving CR and 21 (29%) attaining VGPR. Cardiac response was observed in 11 of 37 evaluable patients (29%) and renal response in 23 of 38 patients (60%). Daratumumab is highly effective in heavily pretreated patients with relapsed/refractory AL amyloidosis and high bone marrow plasma cell burden. Renal responses, which are usually rare in this setting, were frequently observed.

Novel challenges in the management of immunoglobulin light chain amyloidosis: from the bench to the bedside

INTRODUCTION

Immunoglobulin light chain (AL) amyloidosis is one of the most frequent systemic amyloidosis in Western countries. It is caused by a B-cell clone producing a misfolded light chain (LC) that deposits in organs.

AREAS COVERED

The review examines recent findings on pathophysiology and clinical management of AL amyloidosis. It contains an update on the recent hot topics as novel therapeutic approaches, definition of relapse, and hematologic response assessment. To review literature on AL amyloidosis, a bibliographic search was performed using PubMed.

EXPERT OPINION

Due to the proteotoxicity of amyloidogenic LCs, the therapeutic goal is a rapid and profound decrease in their concentration. The standard treatment is a risk-adapted chemotherapy targeting the B-cell clone. Novel, promising drugs, as daratumumab, are currently under evaluation in newly-diagnosed and relapsed/refractory patients. New sensitive techniques, as mass spectrometry approach and bone marrow minimal residual disease assessment, are available to evaluate depth of response. After first-line therapy, increase in LC concentration may precede worsening of organ dysfunction and should be considered carefully. Further clarification of molecular mechanisms of the disease are shedding light on new possible therapeutic targets. Innovative treatment strategies and novel technologies will improve our ability to treat AL amyloidosis, preventing organ deterioration.

A study from The Mayo Clinic evaluated long-term outcomes of kidney transplantation in patients with immunoglobulin light chain amyloidosis

Longer survival using modern therapies has increased the number of patients with immunoglobulin light-chain amyloidosis receiving kidney transplantation. We evaluated 60 patients with immunoglobulin light chain amyloidosis who underwent kidney transplantation based on their hematologic response for outcomes of death, graft failure, and complications. Patient hematologic responses (light-chain in blood or urine) prior to kidney transplantation were three patients had no response, five had a partial response, six had a very good partial response, 37 had a complete response, and nine were treatment-naive patients (never treated for this disorder). After transplantation, seven of nine treatment-naive patients achieved a complete response. The median follow-up for the entire transplant cohort was 61 months. The estimated median overall survival from the time of kidney transplantation was 123 months for the entire group. Median overall survival was not reached for the very good partial response plus complete response groups, it was 47 months for no response plus partial response groups, and 117 months for the treatment-naive group (all significantly different). Median overall survival of very good partial response was 81 months, while the median was not reached in the complete response group (no significant difference). The time to amyloid recurrence was significantly longer in complete response compared to very good partial response (median 181 vs 81 months). Death-censored graft survival at one- and five-years was 98.3%, and 95.8%, respectively for all groups. Of the 60 patients, three had allograft failure, 19 died with a functioning graft, and 13 had an amyloid recurrence. Thus, outcomes after kidney transplant in patients with immunoglobulin light-chain amyloidosis seem acceptable if a very good partial response or complete response is achieved either before or after transplantation.